Sensors and sensor arrays for detection of analytes

ABSTRACT

Methods, apparatus and compositions are described for the measurement of metal and/or metalloid elements, including selenium in samples. More specifically, the invention provides a sensor and/or array of sensors to measure metal and/or metalloid analytes, e.g. sensor and/or array of sensors having a chelator molecule, the chelator molecule including a peptide which has a phenylalanine derivative.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a 371 national stage entry of PCT/US2017/028064,filed on Apr. 18, 2017, which claims the benefit of U.S. ProvisionalPatent Application Nos. 62/324,057, filed Apr. 18, 2016; 62/337,551,filed May 17, 2016; and 62/341,403, filed May 25, 2016; the entirecontents of all of which are herein incorporated by reference.

FIELD

The presently described inventions relate, in part, to sensors andarrays of sensors, as well as methods, compositions and apparatuses, formeasuring metals and/or metalloids. More specifically the inventionsinclude, for example, measuring selenium in environmental water orbiological samples.

DESCRIPTION OF THE TEXT FILE SUBMITTED ELECTRONICALLY

The contents of the text file submitted electronically herewith areincorporated herein by reference in their entirety: A computer readableformat copy of the Sequence Listing (filename:ICA-010PC_Sequence_listing; date recorded: Apr. 18, 2017; file size:4.49 KB).

BACKGROUND

Elemental analysis, which generally refers to the process by which asample (e.g., soil, waste or drinking water, bodily fluids, minerals,etc.) is analyzed for its elemental composition is central to a varietyof analytical techniques that find use in, for example, environmentaland medical applications.

Many metals or metalloids, for example, play important roles inphysiological processes. The human body is exposed to various elementalforms of these metals or metalloids which are ubiquitous in animals,plants, rocks, soil, water, and air. Exposure to these metals ormetalloids can be from air inhalation, food and water intake, surgicalimplants, and occupational scenarios, among others.

Selenium, a metalloid, is among the rarest elements on the surface ofthe planet and it is released through both natural and human activities.For example, exposure of selenium containing minerals to air and watercan mobilize selenium by forming soluble ions such as selenate (SeO₄ ²⁻)and selenite (SeO₃ ²⁻). Solubility increases as the pH decreases. Miningactivities, such as the refining of metal sulfide ores is one source ofmobilized selenium. Selenium is also found in coal in small amounts butwhen coal-bearing strata are exposed to air and water during the miningprocess the selenium is mobilized and forms contaminated leachate, whichoften becomes a source of pollution to nearby surface waters. Coal andother fossil fuel combustion also release selenium to the environment.Well fertilized agricultural soil has about 400 mg/ton of selenium sincethe element is present in phosphate fertilizer.

Elemental forms of selenium include various valence or oxidation states.This speciation can be important because the differing valence statescan have different chemical properties. Common selenium valence statesinclude hexavalent selenium and tetravalent selenium. Also, elementalforms include metals in various valence states. This speciation can beimportant because the differing valence states can have contrastingphysiological effects.

Selenium can be toxic in large amounts, and selenium is often measuredin wastewater to ensure that it is present within acceptableconcentrations. There are currently few selective, sensitive, specific,and inexpensive assays for metals and/or metalloids, inclusive ofselenium, and various species thereof. Additionally, there are currentlyfew assays that differentiate metal and/or metalloid species, forinstance selenium species, by oxidation state. Further, the currenttechnology cannot provide real time detection of selenium quickly. Forinstance, existing methodology such as ICP-MS is effective atmeasurement, but do not have acceptable throughput and turn-around timeto allow responses to mitigate waste stream contamination to occur in anacceptable time frame.

There remains a need for new and improved sensors and arrays of sensorsfor measuring metals and/or metalloids.

SUMMARY

Accordingly, in general, methods, compositions and apparatuses aredisclosed herein for the analysis and determination of various metaland/or metalloid elements, such as selenium. For example, various metaland/or metalloid elements, such as selenium can be selectively detectedin a complex sample including other elements.

In various aspects, the invention provides a sensor and/or array ofsensors to measure metal and/or metalloid analytes (e.g. selenium).

In various aspects, the invention provides a sensor and/or array ofsensors to measure metal and/or metalloid analytes (e.g. selenium)comprising more than one chelator molecule and a solid support, whichare optionally attached to each other. In some embodiments, the chelatormolecule is a peptide, small molecule, or cationic or anionic polymerthat is able to bind to a metal and/or metalloid analyte (e.g.selenium). In some embodiments, the solid support is glass or polymersurface.

In some aspects, the invention provides a sensor and/or array of sensorsto measure metal and/or metalloid analytes (e.g. selenium) using variouschelator molecules capable of concentrating the metal and/or metalloidanalytes (e.g. selenium) from the sample (e.g. solution, including wastewater streams from power plants and other industrial sources).

In some embodiments, the present sensors and/or arrays of sensorscomprise one or more sensors where the sensors that have an ability tobind and detect a metal and/or metalloid analyte of interest. In variousembodiments, the present sensors and/or arrays of sensors comprise oneor more sensors that have an ability to bind and detect a metal and/ormetalloid analyte of interest and the one or more sensors have differentaffinities for the metal and/or metalloid analyte of interest. Forinstance, coupling multiple sensors together which have differingaffinities for the same analyte allows a range of concentrations to bedetected. In various embodiments, the present array allows one to detectanalyte in real time, despite, depending on affinity, one or moreindividual sensors saturating. The present arrays, without wishing to bebound by theory, overcome this saturation issue by providing sensorsthat can detect across a range of analyte concentrations. In variousembodiments, the array of sensors comprises one or more sensors thathave an ability to bind and detect selenium and one or more sensors havedifferent affinities for selenium.

In some embodiments, the present sensors and/or arrays of sensorscomprise one or more sensors where the sensors that have an ability tobind and detect a different species of a single metal and/or metalloidanalyte of interest, inclusive of detection at different concentrations.For instance, in some embodiments, the present sensors and/or arrays ofsensors comprise one or more sensors where the sensors that have anability to bind and detect selenium species selenate and/or selenite.

In some embodiments, the present sensors and/or arrays of sensorscomprise one or more sensors that have an ability to bind and detectdifferent metal and/or metalloid analytes of interest, inclusive atdifferent concentrations. For example, in various embodiments, thepresent sensors and/or arrays of sensors comprise a sensor for seleniumand another element.

In some embodiments, the present sensors and/or arrays of sensors allowfor multiplexed detection of more than one different metal and/ormetalloid analyte of interest, or various forms or species thereof, andvarious ranges of concentrations of the different metal and/or metalloidanalyte of interest.

In some aspects, the invention provides a method for measuring selenium,inclusive of, for example, selenate and/or selenite, in a sample, forexample a liquid sample. Such method includes, in various embodiments,contacting (e.g., combining) a solution containing selenium and sensoras described herein, e.g. comprising a resin capable of concentratingthe selenium from the sample (e.g. solution). In various embodiments,the method also includes measuring a sample of the selenium that isconcentrated on the sensor as described herein, e.g. comprising a resin.The measurement can be, for example, an elemental analysis method. Forexample the elemental analysis may be one or more of x-ray fluorescence,atomic absorption spectroscopy, atomic emission spectroscopy, massspectrometry, and laser induced breakdown spectroscopy. In variousembodiments, the measurement allows for differentiation among species ofselenium, inclusive of, for example, selenate and/or selenite.

In various embodiments, the solid support of the present invention iscapable of concentrating a metal and/or metalloid element from thesample (e.g. solution). In an embodiment of the method, the solidsupport comprises a chelator molecule, such as a peptide.

In various embodiments, the present sensors and/or arrays of sensors aresuitable for measurement using, for example, an elemental analysismethod. For example the elemental analysis may be one or more of x-rayfluorescence, atomic absorption spectroscopy, atomic emissionspectroscopy, mass spectrometry, and laser induced breakdownspectroscopy.

In some aspects, the invention provides a method for measuring a metaland/or metalloid analyte of interest including selenium. Suchmeasurement may allow differentiation of concentrations of the metaland/or metalloid analyte of interest and/or identification of differentmetal and/or metalloid analytes of interest in the same sample. In someembodiments, the metal and/or metalloid analyte of interest is selenium,inclusive of selenate and/or selenite. Such method includes, in variousembodiments, contacting (e.g., combining) a solution containing a metaland/or metalloid analyte of interest, inclusive, without limitation ofselenium, and the present sensors and/or arrays of sensors. In variousembodiments, the method also includes measuring a sample of the seleniumthat is concentrated on the present sensors and/or arrays of sensors.The measurement can be, for example, an elemental analysis method. Forexample the elemental analysis may be one or more of x-ray fluorescence,atomic absorption spectroscopy, atomic emission spectroscopy, massspectrometry, and laser induced breakdown spectroscopy. In variousembodiments, the measurement allows for differentiation among differentmetal and/or metalloid analytes of interest in the same sample. Invarious embodiments, the measurement allows for differentiation amongspecies of selenium, inclusive of, for example, selenate and/orselenite.

Such methods find use in a variety of applications described herein,including, without limitation, environmental analysis for pollution(e.g. air, water) and/or occupational exposure and/or medicalapplications. In various embodiments, the present methods find use inmonitoring waste stream analyte levels, e.g. in effluent from powerplants, mining and refining operations or any other industrial processwhere measurement and detection of certain analytes is required ordesired.

Furthermore, in some embodiments, the x-ray excitation source isdisposed to excite the resin and the x-ray detector is disposed tomeasure x-rays emitted from the sensor (e.g. comprising a resin). Insome embodiments the x-ray detector is an energy dispersive x-raydetector. Alternatively or additionally the x-ray excitation sourceutilizes polychromatic x-rays for exciting the sample. Alternatively oradditionally the x-ray excitation source utilizes a micro-focus x-raytube. In some embodiments the x-ray excitation source utilizes afocusing optic. An embodiment of the present apparatus is found in FIG.1.

Other features and advantages of the invention will be apparent from thefollowing detailed description, drawings, and from the claims.

DESCRIPTION OF THE DRAWINGS

The foregoing will be apparent from the following more particulardescription of example embodiments of the invention, as illustrated inthe accompanying drawings. The drawings are not necessarily to scale,emphasis instead being placed upon illustrating embodiments of thepresent invention.

FIG. 1 shows an apparatus for measuring the x-ray fluorescence emittedfrom sensors and/or arrays of sensors as provided in an embodimentdescribed herein.

FIG. 2 shows a schematic of an illustrative sensor and/or array ofsensors described herein (without limitation, FIG. 2, in someembodiments is element 114 of FIG. 1). FIG. 2 shows a solid support orresin (I) with covalently attached chelators (e.g. peptides, II). In thenon-limiting embodiments shown in FIG. 2, each sensor binds a targetanalyte with varying affinities, leading to overlapping response curves(e.g. as shown in FIG. 3)

FIG. 3 is an illustrative graph showing the differential binding/signalgeneration effect of the sensors and/or arrays of sensors of variousembodiments of the present invention. The varying affinities allow forquantitative measurements over a dynamic range not provided the responseof a single affinity sensor.

FIG. 4 is a chart showing Se/Br counts for selenate selectivity resins.There are three sets of histograms grouped by bead number and for eachset, the histograms are (left to right): preread, first selenateexposure, wash, 2nd selenate exposure, 2nd wash, selenite exposure, andwash.

FIG. 5 is a chart showing Se/Br counts for selenite selective resins.There are three sets of histograms grouped by bead number and for eachset, the histograms are (left to right): first selenite exposure, wash,second selenite exposure, wash, selenate exposure, wash.

DETAILED DESCRIPTION

The sensors and/or arrays of sensors described herein, and methods,apparatuses, and compositions described herein, can provide selective,sensitive, specific, and inexpensive assays for various elements. Forinstance, the methods, apparatuses and compositions described herein canprovide selective, sensitive, specific, and inexpensive assays forselenium, e.g. selenate and/or selenite, exposures.

In various embodiments, the present invention provides for the detectionof metal and/or metalloid elements. For example, detection of seleniumis provided in some embodiments. Particular embodiments relate to theselective detection of metals and/or metalloids, such as selenium, overdynamic ranges that are suited for real time sampling and measurement.Particular embodiments relate to the selective detection of metalsand/or metalloids, such as selenium, in specific oxidation states.Detection can be by any useful means and include detection using a solidsupport or resin to concentrate the metal and/or metalloid and x-rayfluorescence spectroscopy.

Sensors and/or Arrays of Sensors

In various embodiments, the sensors and/or arrays of sensors of thepresent invention comprise more than one sensors for detection, e.g. 2,or 3, or 4, or 5, or 6, or 7, or 8, or 9, or 10 sensors.

In various embodiments, the sensors and/or arrays of sensors of thepresent invention comprise sensors that bind to a metal and/or metalloidanalyte of interest at different affinities from each other. Forinstance, in some embodiments, more than one sensor that binds to ametal and/or metalloid analyte of interest is provided and the varioussensors have affinities for the metal and/or metalloid analyte ofinterest that differ from each other by about 3-, or 5-, or 10-, or 30-,or 50-, or 100-fold. For example, in one embodiment, at least twosensors are provided, the sensors having about a 10-fold difference inaffinity for the metal and/or metalloid analyte of interest. Forexample, in another embodiment, at least three sensors are provided, thesensors each having about a 10-fold difference in affinity for the metaland/or metalloid analyte of interest from each other.

In various embodiments, the sensors and/or arrays of sensors of thepresent invention comprise sensors that bind to selenium at differentaffinities from each other. For instance, in some embodiments, more thanone sensor that binds to selenium is provided and the various sensorshave affinities for selenium that differ from each other by about 3-, or5-, or 10-, or 30-, or 50-, or 100-fold. For example, in one embodiment,at least two sensors are provided, the sensors having about a 10-folddifference in affinity for selenium.

In various embodiments, the sensors and/or arrays of sensors of thepresent invention comprise sensors that bind to a metal and/or metalloidanalyte of interest at different affinities from each other but forwhich the concentration response profiles are overlapping.

In various embodiments, the sensors and/or arrays of sensors havediffering affinity for an analyte of interest and this providesincreased and/or extended sensitivity, dynamic range and selectivity ofmeasurements, e.g. X-ray fluorescence measurements than, for instance,single affinity sensors.

In various embodiments, detection limits are extended through the use ofhigh-affinity sensors. In various embodiments, linear range is extendedthrough the use of multiple sensors with overlapping response ranges.

In various embodiments, the sensors and/or arrays of sensors of thepresent invention comprise sensors that bind to a different, additionalmetal and/or metalloid analytes of interest, and optionally the sensorsfor each of the metal and/or metalloid analytes of interest havedifferent affinities from each other. In some embodiments, the sensorsand/or arrays of sensors bind selenium, optionally with differentaffinities among the selenium sensors, and another analyte, optionallywith different affinities among the other analyte sensors. Illustrativeother analytes include Lithium, Beryllium, Boron, Sodium, Magnesium,Aluminum, Silicon, Potassium, Calcium, Scandium, Titanium, Vanadium,Chromium, Manganese, Iron, Cobalt, Nickel, Copper, Zinc, Gallium,Germanium, Arsenic, Rubidium, Strontium, Yttrium, Zirconium, Niobium,Molybdenum, Technetium, Ruthenium, Rhodium, Palladium, Silver, Cadmium,Indium, Tin, Antimony, Tellurium, Cesium, Barium, Lanthanum, Cerium,Praseodymium, Neodymium, Promethium, Samarium, Europium, Gadolinium,Terbium, Dysprosium, Holmium, Erbium, Thulium, Ytterbium, Lutetium,Hafnium, Tantalum, Tungsten, Rhenium, Osmium, Iridium, Platinum, Gold,Mercury, Thallium, Lead, Bismuth, Francium, Radium, Actinium, Thorium,Protactinium, Uranium, Neptunium, Plutonium, Americium, Curium,Berkelium, Californium, Einsteinium, Fermium, Mendelevium, Nobelium,Lawrencium, Rutherfordium, Dubnium, Seaborgium, Bohrium, Hassium,Meitnerium, Darmstadtium, Roentgenium, Copernicium, Ununtrium,Flerovium, Ununpentium, and Livermorium.

In various embodiments, the sensors and/or arrays of sensors of thepresent invention comprise sensors that bind to a different metal and/ormetalloid analytes of interest (e.g. the sensors and/or arrays ofsensors bind to 2, or 3, or 4, or 5, or 10 metal and/or metalloidanalytes of interest). In various embodiments, the different metaland/or metalloid analyte of interest is known to compete with theprimary metal and/or metalloid analyte of interest for binding tosensors for the primary metal and/or metalloid analyte of interest.

In various embodiments, the sensors and/or arrays of sensors of thepresent invention comprise sensors that bind to different species of ametal and/or metalloid analytes of interest optionally with differentaffinities among the metal and/or metalloid analyte sensors. Forinstance, the present sensors may bind to different oxidation statespecies of the analyte. For example, the present sensors and/or arraysof sensors, in some embodiments, can detect selenate and/or selenite andoptionally have sensors of varying affinities for these species. Forinstance, the present sensors and/or arrays of sensors may binddifferent species of one or more of Lithium, Beryllium, Boron, Sodium,Magnesium, Aluminum, Silicon, Potassium, Calcium, Scandium, Titanium,Vanadium, Chromium, Manganese, Iron, Cobalt, Nickel, Copper, Zinc,Gallium, Germanium, Arsenic, Rubidium, Strontium, Yttrium, Zirconium,Niobium, Molybdenum, Technetium, Ruthenium, Rhodium, Palladium, Silver,Cadmium, Indium, Tin, Antimony, Tellurium, Cesium, Barium, Lanthanum,Cerium, Praseodymium, Neodymium, Promethium, Samarium, Europium,Gadolinium, Terbium, Dysprosium, Holmium, Erbium, Thulium, Ytterbium,Lutetium, Hafnium, Tantalum, Tungsten, Rhenium, Osmium, Iridium,Platinum, Gold, Mercury, Thallium, Lead, Bismuth, Francium, Radium,Actinium, Thorium, Protactinium, Uranium, Neptunium, Plutonium,Americium, Curium, Berkelium, Californium, Einsteinium, Fermium,Mendelevium, Nobelium, Lawrencium, Rutherfordium, Dubnium, Seaborgium,Bohrium, Hassium, Meitnerium, Darmstadtium, Roentgenium, Copernicium,Ununtrium, Flerovium, Ununpentium, and Livermorium and optionally havesensors of varying affinities for these species.

In various embodiments, the sensors and/or arrays of sensors of thepresent invention comprise sensors that bind to a metal and/or metalloidanalyte of interest at different affinities and/or bind to a differentmetal and/or metalloid analytes of interest and/or bind to differentspecies of a metal and/or metalloid analyte of interest.

In various aspects, the invention provides a sensor and/or array ofsensors to measure metal and/or metalloid analytes (e.g. selenium)comprising more than one chelator molecule and a solid support, whichare optionally attached to each other. In some embodiments, the chelatormolecule is a peptide, small molecule, or cationic or anionic polymerthat is able to bind to a metal and/or metalloid analyte (e.g.selenium). In some embodiments, the solid support is glass or polymersurface.

In various embodiments, the sensors and/or arrays of sensors describedherein use and/or comprise a solid support, e.g. resin, which may be inthe form of a particle. In various embodiments, the resin may comprise achelator molecule, which is capable of interacting (e.g. binding) ametal and/or metalloid.

Some aspects of the invention relate to a composition that comprises thesensors and/or arrays of sensors, which may optionally further comprisea chelator molecule, e.g. peptide-based ligand and/or metal and/ormetalloid.

In some embodiments, the chelator molecule, inclusive of peptide-basedligands, can be bound to a surface, such as the surface of a solidsupport. The surface can be an interior or exterior surface of aparticle. For example, a highly porous particle can have a highpercentage of surface area in the particle. For a porous particle, theinterior surface area is preferably accessible to metal and/or metalloidions, therefore having an average pore diameter of at least about 1 nmor larger than about 10 nm (e.g. about 1 nm, or about 5 nm, or about 10nm, or about 25 nm, or about 50 nm, or about 75 nm, or about 100 nm, orabout 200 nm, or about 300 nm, or about 500 nm). The particles can be ofany shape such as an approximate sphere, lozenge, cube, cylinder, fiber,cone, prism, or even an irregularly shaped particle can be used.

In some embodiments, the solid support is glass or polymer surface. Invarious embodiments, the solid support is a resin. In variousembodiments, the resin (or “RESIN” as used herein) is one or morematerials described immediately below, e.g. as components of particles.The particles can be made using inorganic materials (e.g., silicates,aluminosilicates and siloxanes), organic materials (e.g., polystyrene)or combinations of these. Some particles include polystyrene (PS) resinwith some (e.g., 1-2% divinylbenzene) cross linking, also known asMerrifield resin. Other particles include combinations of polyethyleneglycol (PEG) and PS such as PEG grafted on a core of PS, for example,TENTAGEL (Bayer Healthcare, Whippany, N.J.) and HYPOGEL (Rapp PolymereGmbH, Tuebingen, Germany), ARGOGEL (Argonaut Technologies Inc., RedwoodCity, Calif.), and CHAMPION I and II (Biosearch Technologies Inc.,Petaluma, Calif.). Another particle is beadedPoly[acryloyl-bis(aminopropyl)polyethylene glycol] commonly known asPEGA resins. Other illustrative particles include polystyrene crosslinked with tetra(ethylene glycol) diacrylate (TTEGDA), cross likedethoxylated acrylate resin such as CLEAR (Peptides International Inc.,Louisville, Ky.), polyethylene glycol based resins such as CHEMMATRIX(PCAS BioMatrix Inc., Quebec, Canada).

In various embodiments, the RESIN is PEG_(n)-polystyrene, where n is1-10, e.g. 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 (e.g. a TENTAGEL resin).

In some embodiments, the chelator molecule is a peptide, small molecule,or cationic or anionic polymer that is able to bind to a metal and/ormetalloid analyte (e.g. selenium).

In various embodiments, the chelator molecule is a peptide-based ligand.For instance, the peptide may be associated with, e.g. bound to, a solidsupport, e.g. resin, as described herein.

In various embodiments, the peptide has a general formula of:F₁CZ₁Z₂CZ₃Z₄Z₅CF₂,wherein, F₁ and F₂ are each independently a phenylalanine derivative atposition four, as follows:

where X is any element. In some embodiments, X is a halogen. In someembodiments, X is one or more of F, Cl, Br, I and At. In someembodiments, the phenylalanine derivative is 4-bromophenylalanine (F4Br)or 4-iodophenylalanine (F4I), and Z₁, Z₂, Z₃, Z₄, and Z₅ are eachindependently an amino acid, optionally selected from D, I, P, N, H, Q,R, E, W, S, A, G, F, T, L, V, or modifications thereof.

In some embodiments, the peptide is selected from F4ICDICPNHCF4Br (SEQID NO: 1), F4ICQRCERWCF4Br (SEQ ID NO: 2), F4ICFHCFSECF4Br (SEQ ID NO:3), F4ICAGCFTGCF4Br (SEQ ID NO: 4), F4ICQLCNVLCF4Br (SEQ ID NO: 5),F4ICDICPNHC (SEQ ID NO: 6), F4ICQRCERWC (SEQ ID NO: 7), F4ICHTCFQTC (SEQID NO: 8), YBrCR(T/Q)SC (SEQ ID NO: 9) (e.g. YBrCRTSC (SEQ ID NO: 10),YBrCRQSC (SEQ ID NO: 11)), and YmICR(T/Q)SC (SEQ ID NO: 12) (e.g.YmICRTSC (SEQ ID NO: 13), YmICRQSC (SEQ ID NO: 14)) or variants thereof.As used herein, “F4Br” is 4-bromophenylalanine, “F4I” is4-iodophenylalanine, “YBr” is 3,5-dibromotyrosine, and “YmI” ismono-iodo tyrosine.

In some embodiments, the peptide binds selenate and has a sequenceselected from selected from F4ICDICPNHCF4Br (SEQ ID NO: 1),F4ICQRCERWCF4Br (SEQ ID NO: 2), F4ICFHCFSECF4Br (SEQ ID NO: 3), orvariants thereof.

In various embodiments, the peptide has a general formula ofY₁CRX₁SCwherein: X₁ is Q or T and Y₁ is a tyrosine derivative at the three andfive positions of the structure:

andY and Z are a halogen or one or Y and Z is a halogen and one of Y and Zis hydrogen.

In various embodiments, Y₁ is 3,5-dibromotyrosine or mono-iodo-tyrosine.

In various embodiments, the peptide comprises one or more of YBrCRTSC(SEQ ID NO: 10), YBrCRQSC (SEQ ID NO: 11), YmICRTSC (SEQ ID NO: 13), andYmICRQSC (SEQ ID NO: 14).

In some embodiments, the peptide binds selenite and has a sequenceselected from F4ICAGCFTGCF4Br (SEQ ID NO: 4), F4ICQLCNVLCF4Br (SEQ IDNO: 5), YBrCR(T/Q)SC (SEQ ID NO: 9) (e.g. YBrCRTSC (SEQ ID NO: 10),YBrCRQSC (SEQ ID NO: 11)) and YmICR(T/Q)SC (SEQ ID NO: 12) (e.g.YmICRTSC (SEQ ID NO: 13), YmICRQSC (SEQ ID NO: 14)), or variantsthereof.

In some embodiments, the sensor and/or array of sensors comprises apeptide and has a structure selected from F4ICDICPNHCF4Br-RESIN (SEQ IDNO: 1-RESIN), F4ICQRCERWCF4Br-RESIN (SEQ ID NO: 2-RESIN),F4ICFHCFSECF4Br-RESIN (SEQ ID NO: 3-RESIN), F4ICAGCFTGCF4Br-RESIN (SEQID NO: 4-RESIN), F4ICQLCNVLCF4Br-RESIN (SEQ ID NO: 5-RESIN),F4ICDICPNHC-RESIN (SEQ ID NO: 6-RESIN), F4ICQRCERWC-RESIN (SEQ ID NO:7-RESIN), F4ICHTCFQTC-RESIN (SEQ ID NO: 8-RESIN), YBrCR(T/Q)SC-RESIN(SEQ ID NO: 9-RESIN) (e.g. YBrCRTSC-RESIN (SEQ ID NO: 10-RESIN),YBrCRQSC-RESIN (SEQ ID NO: 11-RESIN)), and YmICR(T/Q)SC-RESIN (SEQ IDNO: 12-RESIN) (e.g. YmICRTSC-RESIN (SEQ ID NO: 12-RESIN), YmICRQSC-RESIN(SEQ ID NO: 13-RESIN)) or RESIN-F4ICDICPNHCF4Br (RESIN-SEQ ID NO: 1),RESIN-F4ICQRCERWCF4Br (RESIN-SEQ ID NO: 2), RESIN-F4ICFHCFSECF4Br(RESIN-SEQ ID NO: 3), RESIN-F4ICAGCFTGCF4Br (RESIN-SEQ ID NO: 4),RESIN-F4ICQLCNVLCF4Br (RESIN-SEQ ID NO: 5), RESIN-YBrCR(T/Q)SC(RESIN-SEQ ID NO: 9) (e.g. RESIN-YBrCRTSC (RESIN-SEQ ID NO: 10),RESIN-YBrCRQSC (RESIN-SEQ ID NO: 11)), and RESIN-YmICR(T/Q)SC (RESIN-SEQID NO: 12) (e.g. RESIN YmICRTSC (RESIN-SEQ ID NO: 13), RESIN-YmICRQSC(RESIN-SEQ ID NO: 14)). In various embodiments the RESIN isPEG_(n)-polystyrene, where n is 1-10, e.g. 1, 2, 3, 4, 5, 6, 7, 8, 9,and 10 (e.g. a TENTAGEL resin).

In some embodiments, the solution comprises selenate and the sensorand/or array of sensors has a structure selected fromF4ICDICPNHCF4Br-RESIN (SEQ ID NO: 1-RESIN), F4ICQRCERWCF4Br-RESIN (SEQID NO: 2-RESIN), F4ICFHCFSECF4Br-RESIN (SEQ ID NO: 3-RESIN), or variantsthereof.

In some embodiments, the solution comprises selenite and the sensorand/or array of sensors has a structure selected F4ICAGCFTGCF4Br-RESIN(SEQ ID NO: 4-RESIN), F4ICQLCNVLCF4Br-RESIN (SEQ ID NO: 5-RESIN),YBrCR(T/Q)SC-RESIN (SEQ ID NO: 9-RESIN) (e.g. YBrCRTSC-RESIN (SEQ ID NO:10-RESIN), YBrCRQSC-RESIN (SEQ ID NO: 11-RESIN)), and YmICR(T/Q)SC-RESIN(SEQ ID NO: 12-RESIN) (e.g. YmICRTSC-RESIN (SEQ ID NO: 13-RESIN),YmICRQSC-RESIN (SEQ ID NO: 14-RESIN)) or variants thereof.

In some embodiments, the invention provides for variants of thesequences listed. In some embodiments, the variants are functionallycomparable variants.

For example, the present peptides may comprise alterations that do notsubstantially affect suitability for the uses described herein. Forexample, one, or two, or three, or four, or five amino acids may bemutated. In some embodiments, the mutation is a substitution. In someembodiments, the mutation is a deletion. In some embodiments, themutation is an addition. Illustrative mutations are substitutions oradditions, which can be conservative or non-conservative in nature.

Conservative substitutions may be made, for instance, on the basis ofsimilarity in polarity, charge, size, solubility, hydrophobicity,hydrophilicity, and/or the amphipathic nature of the amino acid residuesinvolved. The 20 naturally occurring amino acids can be grouped into thefollowing six standard amino acid groups: (1) hydrophobic: Met, Ala,Val, Leu, Ile; (2) neutral hydrophilic: Cys, Ser, Thr; Asn, Gln; (3)acidic: Asp, Glu; (4) basic: His, Lys, Arg; (5) residues that influencechain orientation: Gly, Pro; and (6) aromatic: Trp, Tyr, Phe.Conservative substitutions may be as exchanges of an amino acid byanother amino acid listed within the same group of the six standardamino acid groups shown above. For example, glycine and proline may besubstituted for one another based on their ability to disrupt α-helices.

Non-conservative substitutions may be exchanges of an amino acid byanother amino acid listed in a different group of the six standard aminoacid groups (1) to (6) shown above.

In some embodiments, the peptide comprises at least one non-classicalamino acid. Illustrative non-classical amino acids includeselenocysteine, pyrrolysine, N-formylmethionine β-alanine, GABA andδ-Aminolevulinic acid, 4-aminobenzoic acid (PABA), D-isomers of thecommon amino acids, 2,4-diaminobutyric acid, α-amino isobutyric acid,4-aminobutyric acid, Abu, 2-amino butyric acid, γ-Abu, ε-Ahx, 6-aminohexanoic acid, Aib, 2-amino isobutyric acid, 3-amino propionic acid,ornithine, norleucine, norvaline, hydroxyproline, sarcosme, citrulline,homocitrulline, cysteic acid, t-butylglycine, t-butylalanine,phenylglycine, cyclohexylalanine, β-alanine, fluoro-amino acids,designer amino acids such as β methyl amino acids, C α-methyl aminoacids, N α-methyl amino acids, and amino acid analogs in general).

Further, in various embodiments mutations, inclusive of substitutionsand additions, may also include non-classical amino acids as describedherein.

In some embodiments, the peptide comprises a non-classical amino acidwhich is a phenylalanine derivative at the four position, as follows:

where X is any element. In some embodiments, X is a halogen. In someembodiments, X is one or more of F, Cl, Br, I and At. In someembodiments, the non-classical amino acid is 4-bromophenylalanine and/or4-iodophenylalanine. In specific embodiments, the phenylalaninederivative precedes and/or succeeds the following sequences: CDICPNHC,CQRCERWC, CFHCFSEC, CAGCFTGC, and CQLCNVLC.

In some embodiments, the peptide is one or more of F4ICDICPNHCF4Br (SEQID NO: 1), F4ICQRCERWCF4Br (SEQ ID NO: 2), F4ICFHCFSECF4Br (SEQ ID NO:3), F4ICAGCFTGCF4Br (SEQ ID NO: 4), F4ICQLCNVLCF4Br (SEQ ID NO: 5),F4ICDICPNHC (SEQ ID NO: 6), F4ICQRCERWC (SEQ ID NO: 7), F4ICHTCFQTC (SEQID NO: 8), or variants thereof and the F4Br may be substituted for4-iodophenylalanine (F4I), 4-chlorophenylalanine (F4Cl), or4-fluorophenylalanine (F4F). In some embodiments, the peptide is one ormore of F4ICDICPNHCF4Br (SEQ ID NO: 1), F4ICQRCERWCF4Br (SEQ ID NO: 2),F4ICFHCFSECF4Br (SEQ ID NO: 3), F4ICAGCFTGCF4Br (SEQ ID NO: 4),F4ICQLCNVLCF4Br (SEQ ID NO: 5), or variants thereof and the F4I may besubstituted for 4-fluorophenylalanine (F4F), 4-chlorophenylalanine(F4Cl), or 4-bromophenylalanine (F4Br). In some embodiments, the peptideis one or more of F4ICDICPNHCF4Br (SEQ ID NO: 1), F4ICQRCERWCF4Br (SEQID NO: 2), F4ICFHCFSECF4Br (SEQ ID NO: 3), F4ICAGCFTGCF4Br (SEQ ID NO:4), F4ICQLCNVLCF4Br (SEQ ID NO: 5), or variants thereof and the F4Br maybe substituted for 4-iodophenylalanine (F4I), 4-chlorophenylalanine(F4Cl), or 4-fluorophenylalanine (F4F) and the F4I may be substitutedfor 4-fluorophenylalanine (F4F), 4-chlorophenylalanine (F4Cl), or4-bromophenylalanine (F4Br).

In some embodiments, the peptide comprises a non-classical amino acidwhich is a tyrosine derivative at the three and five positions, asfollows:

where Y and Z are each independently any element. In some embodiments, Yand/or Z are a halogen. In some embodiments, one of X or Y is a halogenand the other is a hydrogen. In some embodiments, Y and/or Z is one ormore of F, Cl, Br, I and At. In some embodiments, one of Y and Z ishydrogen and one of Y and Z is selected from F, Cl, Br, I and At. In aspecific embodiment, Y is hydrogen and Z is selected from F, Cl, Br, Iand At. In some embodiments, the non-classical amino acid ismono-iodo-tyrosine, a/k/a N-Iodo-L-tyrosine (“YmI”). In someembodiments, the non-classical amino acid is 3,5-dibromotyrosine. Inspecific embodiments, the tyrosine derivative precedes the sequenceCRTSC (SEQ ID NO: 15) or CRQSC (SEQ ID NO: 16).

Alternatively or additionally the sensor, e.g. the chelator molecule(e.g. peptide) includes an element having an atomic number greater 11.In yet another embodiment of the method the solid support, e.g. resin,comprises a chemical element having an atomic number greater than 11.Optionally, the method can also include measuring a sample of theelement. Optionally the method can further include calculating the ratiobetween a metal and/or metalloid element (e.g. selenium) and theelement. In various embodiments, the chemical element having an atomicnumber greater than 11 is useful as an internal quantitative standardfor the measurement methods of the present invention (e.g. the elementis present at a known stoichiometry). In various embodiments, thechemical element having an atomic number greater than 11 is useful as abarcoding system for identification of the chelator in a mixture orunordered array.

In various embodiments, the element may be one or more of 12: Magnesium,13: Aluminum, 14: Silicon, 15: Phosphorus, 16: Sulfur, 17: Chlorine, 18:Argon, 19: Potassium, 20: Calcium, 21: Scandium, 22: Titanium, 23:Vanadium, 25: Manganese, 26: Iron, 27: Cobalt, 28: Nickel, 29: Copper,30: Zinc, 31: Gallium, 32: Germanium, 33: Arsenic, 35: Bromine, 36:Krypton, 37: Rubidium, 38: Strontium, 39: Yttrium, 40: Zirconium, 41:Niobium, 42: Molybdenum, 43: Technetium, 44: Ruthenium, 45: Rhodium, 46:Palladium, 47: Silver, 48: Cadmium, 49: Indium, 50: Tin, 51: Antimony,52: Tellurium, 53: Iodine, 54: Xenon, 55: Cesium, 56: Barium, 57:Lanthanum, 58: Cerium, 59: Praseodymium, 60: Neodymium, 61: Promethium,62: Samarium, 63: Europium, 64: Gadolinium, 65: Terbium, 66: Dysprosium,67: Holmium, 68: Erbium, 69: Thulium, 70: Ytterbium, 71: Lutetium, 72:Hafnium, 73: Tantalum, 74: Tungsten, 75: Rhenium, 76: Osmium, 77:Iridium, 78: Platinum, 79: Gold, 80: Mercury, 81: Thallium, 82: Lead,83: Bismuth, 84: Polonium, 85: Astatine, 86: Radon, 87: Francium, 88:Radium, 89: Actinium, 90: Thorium, 91: Protactinium, 92: Uranium, 93:Neptunium, 94: Plutonium, 95: Americium, 96: Curium, 97: Berkelium, 98:Californium, 99: Einsteinium, 100: Fermium, 101: Mendelevium, 102:Nobelium, 103: Lawrencium, 104: Rutherfordium, 105: Dubnium, 106:Seaborgium, 107: Bohrium, 108: Hassium, 109: Meitnerium, 110:Darmstadtium, 111: Roentgenium, 112: Copernicium, 113: Ununtrium, 114:Flerovium, 115: Ununpentium, 116: Livermorium, 117: Ununseptium, and118: Ununoctium.

In some embodiments, the element is Se, Br, I, Cl, S, or P.

For example, in some embodiments, the present invention is used todetermine a ratio of selenium to a second element, or third element, orfourth element or fifth element. For example, in some embodiments, thepresent invention is used to determine a ratio of selenium to bromine.

In some embodiments, the sensor and/or array of sensors comprises apeptide and has a structure selected from F4ICDICPNHCF4Br-RESIN (SEQ IDNO: 1-RESIN), F4ICQRCERWCF4Br-RESIN (SEQ ID NO: 2-RESIN),F4ICFHCFSECF4Br-RESIN (SEQ ID NO: 3-RESIN), F4ICAGCFTGCF4Br-RESIN (SEQID NO: 4-RESIN), F4ICQLCNVLCF4Br-RESIN (SEQ ID NO: 5-RESIN),YBrCR(T/Q)SC-RESIN (SEQ ID NO: 9-RESIN) (e.g. YBrCRTSC-RESIN (SEQ ID NO:10-RESIN), YBrCRQSC-RESIN (SEQ ID NO: 11-RESIN)), F4ICDICPNHC-RESIN (SEQID NO: 6-RESIN), F4ICQRCERWC-RESIN (SEQ ID NO: 7-RESIN),F4ICHTCFQTC-RESIN (SEQ ID NO: 8-RESIN), and YmICR(T/Q)SC-RESIN (SEQ IDNO: 12-RESIN) (e.g. YmICRTSC (SEQ ID NO: 13)-RESIN, YmICRQSC (SEQ ID NO:14)-RESIN) or RESIN-F4ICDICPNHCF4Br (RESIN-SEQ ID NO: 1),RESIN-F4ICQRCERWCF4Br (RESIN-SEQ ID NO: 2), RESIN-F4ICFHCFSECF4Br(RESIN-SEQ ID NO: 3), RESIN-F4ICAGCFTGCF4Br (RESIN-SEQ ID NO: 4),RESIN-F4ICQLCNVLCF4Br (RESIN-SEQ ID NO: 5), RESIN-F4ICDICPNHC (RESIN-SEQID NO: 6), RESIN-F4ICQRCERWC (SEQ ID NO: 7), RESIN-F4ICHTCFQTC(RESIN-SEQ ID NO: 8), RESIN-YBrCR(T/Q)SC (RESIN-SEQ ID NO: 9) (e.g.RESIN-YBrCRTSC (RESIN-SEQ ID NO: 10), RESIN-YBrCRQSC (RESIN-SEQ ID NO:11)), and RESIN-YmICR(T/Q)SC (RESIN-SEQ ID NO: 12) (e.g. RESIN YmICRTSC(RESIN-SEQ ID NO: 13), RESIN-YmICRQSC (RESIN-SEQ ID NO: 14)).

In some embodiments, the sensor and/or array of sensors comprises apeptide and has a structure selected fromF4ICDICPNHCF4Br-PEG4-Polystyrene (SEQ ID NO: 1-PEG4-Polystyrene),F4ICQRCERWCF4Br-PEG4-Polystyrene (SEQ ID NO: 2-PEG4-Polystyrene),F4ICFHCFSECF4Br-PEG4-Polystyrene (SEQ ID NO: 3-PEG4-Polystyrene),F4ICAGCFTGCF4Br-PEG4-Polystyrene (SEQ ID NO: 4-PEG4-Polystyrene),F4ICQLCNVLCF4Br-PEG4-Polystyrene (SEQ ID NO: 5-PEG4-Polystyrene),YBrCR(T/Q)SC-PEG4-Polystyrene (SEQ ID NO: 9-PEG4-Polystyrene) (e.g.YBrCRTSC-PEG4-Polystyrene (SEQ ID NO: 10-PEG4-Polystyrene),YBrCRQSC-PEG4-Polystyrene (SEQ ID NO: 11-PEG4-Polystyrene)) andYmICR(T/Q)SC-PEG4-Polystyrene (SEQ ID NO: 12-PEG4-Polystyrene) (e.g.YmICRTSC-PEG4-Polystyrene (SEQ ID NO: 13-PEG4-Polystyrene),YmICRQSC-PEG4-Polystyrene (SEQ ID NO: 14-PEG4-Polystyrene) orPolystyrene-PEG4-F4ICDICPNHCF4Br (Polystyrene-PEG4-SEQ ID NO: 1),Polystyrene-PEG4-F4ICQRCERWCF4Br (Polystyrene-PEG4-SEQ ID NO: 2),Polystyrene-PEG4-F4ICFHCFSECF4Br (Polystyrene-PEG4-SEQ ID NO: 3),Polystyrene-PEG4-F4ICAGCFTGCF4Br (Polystyrene-PEG4-SEQ ID NO: 4),Polystyrene-PEG4-F4ICQLCNVLCF4Br (Polystyrene-PEG4-SEQ ID NO: 5),Polystyrene-PEG4-YBrCR(T/Q)SC (Polystyrene-PEG4-SEQ ID NO: 9) (e.g.Polystyrene-PEG4-YBrCRTSC (Polystyrene-PEG4-SEQ ID NO: 10),Polystyrene-PEG4-YBrCRQSC (Polystyrene-PEG4-SEQ ID NO: 11)) andPolystyrene-PEG4-YmICR(T/Q)SC (Polystyrene-PEG4-SEQ ID NO: 12) (e.g.Polystyrene-PEG4-YmICRTSC (Polystyrene-PEG4-SEQ ID NO: 13),Polystyrene-PEG4-YmICRQSC (Polystyrene-PEG4-SEQ ID NO: 14)).

In some embodiments the solution comprises selenate and the sensorand/or array of sensors comprises a peptide and has a structure selectedfrom F4ICDICPNHCF4Br-RESIN (SEQ ID NO:1-RESIN), F4ICQRCERWCF4Br-RESIN(SEQ ID NO:2-RESIN), F4ICFHCFSECF4Br-RESIN (SEQ ID NO: 3-RESIN). In someembodiments the solution comprises selenate and the resin comprises apeptide and has a structure selected fromF4ICDICPNHCF4Br-PEG4-Polystyrene (SEQ ID NO:1-PEG4-Polystyrene),F4ICQRCERWCF4Br-PEG4-Polystyrene (SEQ ID NO:2-PEG4-Polystyrene),F4ICFHCFSECF4Br-PEG4-Polystyrene (SEQ ID NO: 3-PEG4-Polystyrene).

In some embodiments the solution comprises selenite and the sensorand/or array of sensors comprises a peptide and has a structure selectedfrom F4ICAGCFTGCF4Br-RESIN (SEQ ID NO: 4-RESIN), F4ICQLCNVLCF4Br-RESIN(SEQ ID NO: 5-RESIN), YBrCR(T/Q)SC-RESIN (SEQ ID NO: 9-RESIN) (e.g.YBrCRTSC-RESIN (SEQ ID NO: 10-RESIN), YBrCRQSC-RESIN (SEQ ID NO:11-RESIN)) and YmICR(T/Q)SC-RESIN (SEQ ID NO: 12-RESIN) (e.g.YmICRTSC-RESIN (SEQ ID NO: 13-RESIN), YmICRQSC-RESIN (SEQ ID NO:14-RESIN)). In some embodiments the solution comprises selenite and thesensor and/or array of sensors comprises a peptide and has a structureselected from F4ICAGCFTGCF4Br-PEG4-Polystyrene (SEQ ID NO:4-PEG4-Polystyrene), F4ICQLCNVLCF4Br-PEG4-Polystyrene (SEQ ID NO:5-PEG4-Polystyrene), YBrCR(T/Q)SC-PEG4-Polystyrene (SEQ ID NO:9-PEG4-Polystyrene) (e.g. YBrCRTSC-PEG4-Polystyrene (SEQ ID NO:10-Polystyrene-PEG4), YBrCRQSC-PEG4-Polystyrene (SEQ ID NO:11-PEG4-Polystyrene)) and YmICR(T/Q)SC-PEG4-Polystyrene (SEQ ID NO:12-PEG4-Polystyrene) (e.g. YmICRTSC-PEG4-Polystyrene (SEQ ID NO:13-PEG4-Polystyrene), YmICRQSC-PEG4-Polystyrene (SEQ ID NO:14-PEG4-Polystyrene)).

In a specific embodiment, the invention provides a compositioncomprising a sensor and/or array of sensors, which is comprises apeptide. In a specific embodiment, the invention provides a compositioncomprising a sensor and/or array of sensors, which comprises a peptide,the peptide comprising one or more of F4ICDICPNHCF4Br (SEQ ID NO: 1),F4ICQRCERWCF4Br (SEQ ID NO: 2), F4ICFHCFSECF4Br (SEQ ID NO: 3),F4ICAGCFTGCF4Br (SEQ ID NO: 4), F4ICQLCNVLCF4Br (SEQ ID NO: 5),YBrCR(T/Q)SC (SEQ ID NO: 9) (e.g. YBrCRTSC (SEQ ID NO: 10), YBrCRQSC(SEQ ID NO: 11)) and YmICR(T/Q)SC (SEQ ID NO: 12) (e.g. YmICRTSC (SEQ IDNO: 13), YmICRQSC (SEQ ID NO: 14)), or variants thereof. In someembodiments, the composition comprises two or more of F4ICDICPNHCF4Br(SEQ ID NO: 1), F4ICQRCERWCF4Br (SEQ ID NO: 2), F4ICFHCFSECF4Br (SEQ IDNO: 3), F4ICAGCFTGCF4Br (SEQ ID NO: 4), F4ICQLCNVLCF4Br (SEQ ID NO: 5),YBrCR(T/Q)SC (SEQ ID NO: 9) (e.g. YBrCRTSC (SEQ ID NO: 10), YBrCRQSC(SEQ ID NO: 11)), and YmICR(T/Q)SC (SEQ ID NO: 12) (e.g. YmICRTSC (SEQID NO: 13), YmICRQSC (SEQ ID NO: 14)), or variants thereof. In someembodiments, the composition comprises three or more of F4ICDICPNHCF4Br(SEQ ID NO: 1), F4ICQRCERWCF4Br (SEQ ID NO: 2), F4ICFHCFSECF4Br (SEQ IDNO: 3), F4ICAGCFTGCF4Br (SEQ ID NO: 4), F4ICQLCNVLCF4Br (SEQ ID NO: 5),YBrCR(T/Q)SC (SEQ ID NO: 9) (e.g. YBrCRTSC (SEQ ID NO: 10), YBrCRQSC(SEQ ID NO: 11)), and YmICR(T/Q)SC (SEQ ID NO: 12) (e.g. YmICRTSC (SEQID NO: 13), YmICRQSC (SEQ ID NO: 14)) or variants thereof. In someembodiments, the composition comprises four of F4ICDICPNHCF4Br (SEQ IDNO: 1), F4ICQRCERWCF4Br (SEQ ID NO: 2), F4ICFHCFSECF4Br (SEQ ID NO: 3),F4ICAGCFTGCF4Br (SEQ ID NO: 4), F4ICQLCNVLCF4Br (SEQ ID NO: 5),YBrCR(T/Q)SC (SEQ ID NO: 9) (e.g. YBrCRTSC (SEQ ID NO: 10), YBrCRQSC(SEQ ID NO: 11)), and YmICR(T/Q)SC (SEQ ID NO: 12) (e.g. YmICRTSC (SEQID NO: 13), YmICRQSC (SEQ ID NO: 14)) or variants thereof. In someembodiments, the composition comprises five of F4ICDICPNHCF4Br (SEQ IDNO: 1), F4ICQRCERWCF4Br (SEQ ID NO: 2), F4ICFHCFSECF4Br (SEQ ID NO: 3),F4ICAGCFTGCF4Br (SEQ ID NO: 4), F4ICQLCNVLCF4Br (SEQ ID NO: 5),YBrCR(T/Q)SC (SEQ ID NO: 9) (e.g. YBrCRTSC (SEQ ID NO: 10), YBrCRQSC(SEQ ID NO: 11)), and YmICR(T/Q)SC (SEQ ID NO: 12) (e.g. YmICRTSC (SEQID NO: 13), YmICRQSC (SEQ ID NO: 14)) or variants thereof. In someembodiments, the composition comprises six of F4ICDICPNHCF4Br (SEQ IDNO: 1), F4ICQRCERWCF4Br (SEQ ID NO: 2), F4ICFHCFSECF4Br (SEQ ID NO: 3),F4ICAGCFTGCF4Br (SEQ ID NO: 4), F4ICQLCNVLCF4Br (SEQ ID NO: 5),YBrCR(T/Q)SC (SEQ ID NO: 9) (e.g. YBrCRTSC (SEQ ID NO: 10), YBrCRQSC(SEQ ID NO: 11)), and YmICR(T/Q)SC (SEQ ID NO: 12) (e.g. YmICRTSC (SEQID NO: 13), YmICRQSC (SEQ ID NO: 14)) or variants thereof. Suchcompositions may find use in detection of one or both of selenite andselenate. Such peptides may bind an analyte at differing affinities asdescribed elsewhere herein.

In a specific embodiment, the invention provides a sensor and/or arrayof sensors comprising a resin, which is associated with a peptide forthe detection of selenate, the peptide having a sequence selected fromF4ICDICPNHCF4Br (SEQ ID NO: 1), F4ICQRCERWCF4Br (SEQ ID NO: 2),F4ICFHCFSECF4Br (SEQ ID NO: 3), or variants thereof.

In a specific embodiment, the invention provides a sensor and/or arrayof sensors comprising a resin, which is associated with a peptide forthe detection of selenite, the peptide having a sequence selected fromF4ICAGCFTGCF4Br (SEQ ID NO: 4), F4ICQLCNVLCF4Br (SEQ ID NO: 5),YBrCR(T/Q)SC (SEQ ID NO: 9) (e.g. YBrCRTSC (SEQ ID NO: 10), YBrCRQSC(SEQ ID NO: 11)), and YmICR(T/Q)SC (SEQ ID NO: 12) (e.g. YmICRTSC (SEQID NO: 13), YmICRQSC (SEQ ID NO: 14)), or variants thereof.

As described above, the peptides of the sensor and/or array of sensorsmay be mutated.

The present sensor and/or array of sensors may comprise one or more ofF4ICDICPNHCF4Br-RESIN (SEQ ID NO: 1-RESIN), F4ICQRCERWCF4Br-RESIN (SEQID NO: 2-RESIN), F4ICFHCFSECF4Br-RESIN (SEQ ID NO: 3-RESIN),F4ICAGCFTGCF4Br-RESIN (SEQ ID NO: 4-RESIN), F4ICQLCNVLCF4Br-RESIN (SEQID NO: 5), YBrCR(T/Q)SC-RESIN (SEQ ID NO: 9-RESIN) (e.g. YBrCRTSC-RESIN(SEQ ID NO: 10-RESIN), YBrCRQSC-RESIN (SEQ ID NO: 11-RESIN)) andYmICR(T/Q)SC-RESIN (SEQ ID NO: 12-RESIN) (e.g. YmICRTSC-RESIN (SEQ IDNO: 13-RESIN), YmICRQSC-RESIN (SEQ ID NO: 14-RESIN)) orRESIN-F4ICDICPNHCF4Br (RESIN-SEQ ID NO: 1), RESIN-F4ICQRCERWCF4Br(RESIN-SEQ ID NO: 2), RESIN-F4ICFHCFSECF4Br (RESIN-SEQ ID NO: 3),RESIN-F4ICAGCFTGCF4Br (RESIN-SEQ ID NO: 4), RESIN-F4ICQLCNVLCF4Br(RESIN-SEQ ID NO: 5), RESIN-YBrCR(T/Q)SC (RESIN-SEQ ID NO: 9) (e.g.RESIN-YBrCRTSC (RESIN-SEQ ID NO: 10), RESIN-YBrCRQSC (RESIN-SEQ ID NO:11)) and RESIN-YmICR(T/Q)SC (RESIN-SEQ ID NO: 12) (e.g. RESIN-YmICRTSC(RESIN-SEQ ID NO: 13), RESIN-YmICRQSC (RESIN-SEQ ID NO: 14)). Thepresent sensor and/or array of sensors may comprise one ofF4ICDICPNHCF4Br-RESIN (SEQ ID NO: 1-RESIN), F4ICQRCERWCF4Br-RESIN (SEQID NO: 2-RESIN), F4ICFHCFSECF4Br-RESIN (SEQ ID NO: 3-RESIN),F4ICAGCFTGCF4Br-RESIN (SEQ ID NO: 4-RESIN), F4ICQLCNVLCF4Br-RESIN (SEQID NO: 5-RESIN), YBrCR(T/Q)SC-RESIN (SEQ ID NO: 9-RESIN) (e.g.YBrCRTSC-RESIN (SEQ ID NO: 10-RESIN), YBrCRQSC-RESIN (SEQ ID NO:11-RESIN)) and YmICR(T/Q)SC-RESIN (SEQ ID NO: 12-RESIN) (e.g.YmICRTSC-RESIN (SEQ ID NO: 13-RESIN), YmICRQSC-RESIN (SEQ ID NO:14-RESIN)) or RESIN-F4ICDICPNHCF4Br (RESIN-SEQ ID NO: 1),RESIN-F4ICQRCERWCF4Br (RESIN-SEQ ID NO: 2), RESIN-F4ICFHCFSECF4Br(RESIN-SEQ ID NO: 3), RESIN-F4ICAGCFTGCF4Br (RESIN-SEQ ID NO: 4),RESIN-F4ICQLCNVLCF4Br (RESIN-SEQ ID NO: 5), RESIN-YBrCR(T/Q)SC(RESIN-SEQ ID NO: 9) (e.g. RESIN-YBrCRTSC (RESIN-SEQ ID NO: 10),RESIN-YBrCRQSC (RESIN-SEQ ID NO: 11)) and RESIN-YmICR(T/Q)SC (RESIN-SEQID NO: 12-RESIN) (e.g. RESIN-YmICRTSC (RESIN-SEQ ID NO: 13),RESIN-YmICRQSC (RESIN-SEQ ID NO: 14)). The present sensor and/or arrayof sensors may comprise two of F4ICDICPNHCF4Br-RESIN (SEQ ID NO:1-RESIN), F4ICQRCERWCF4Br-RESIN (SEQ ID NO: 2-RESIN),F4ICFHCFSECF4Br-RESIN (SEQ ID NO: 3-RESIN), F4ICAGCFTGCF4Br-RESIN (SEQID NO: 4-RESIN), F4ICQLCNVLCF4Br-RESIN (SEQ ID NO: 5-RESIN),YBrCR(T/Q)SC-RESIN (SEQ ID NO: 9-RESIN) (e.g. YBrCRTSC-RESIN (SEQ ID NO:10-RESIN), YBrCRQSC-RESIN (SEQ ID NO: 11-RESIN)) and YmICR(T/Q)SC-RESIN(SEQ ID NO: 12-RESIN) (e.g. YmICRTSC-RESIN (SEQ ID NO: 13-RESIN),YmICRQSC-RESIN (SEQ ID NO: 14-RESIN)) or RESIN-F4ICDICPNHCF4Br(RESIN-SEQ ID NO: 1), RESIN-F4ICQRCERWCF4Br (RESIN-SEQ ID NO: 2),RESIN-F4ICFHCFSECF4Br (RESIN-SEQ ID NO: 3), RESIN-F4ICAGCFTGCF4Br(RESIN-SEQ ID NO: 4), RESIN-F4ICQLCNVLCF4Br (RESIN-SEQ ID NO: 5),RESIN-YBrCR(T/Q)SC (RESIN-SEQ ID NO: 9) (e.g. RESIN-YBrCRTSC (RESIN-SEQID NO: 10), RESIN-YBrCRQSC (RESIN-SEQ ID NO: 11)) and RESIN-YmICR(T/Q)SC(RESIN-SEQ ID NO: 12) (e.g. RESIN-YmICRTSC (RESIN-SEQ ID NO: 13),RESIN-YmICRQSC (RESIN-SEQ ID NO: 14)). The present sensor and/or arrayof sensors may comprise three of F4ICDICPNHCF4Br-RESIN (SEQ ID NO:1-RESIN), F4ICQRCERWCF4Br-RESIN (SEQ ID NO: 2-RESIN),F4ICFHCFSECF4Br-RESIN (SEQ ID NO: 3-RESIN), F4ICAGCFTGCF4Br-RESIN (SEQID NO: 4-RESIN), F4ICQLCNVLCF4Br-RESIN (SEQ ID NO: 5-RESIN),YBrCR(T/Q)SC-RESIN (SEQ ID NO: 9-RESIN) (e.g. YBrCRTSC-RESIN (SEQ ID NO:10-RESIN), YBrCRQSC-RESIN (SEQ ID NO: 11-RESIN)) and YmICR(T/Q)SC-RESIN(SEQ ID NO: 12-RESIN) (e.g. YmICRTSC-RESIN (SEQ ID NO: 13-RESIN),YmICRQSC-RESIN (SEQ ID NO: 14-RESIN)) or RESIN-F4ICDICPNHCF4Br(RESIN-SEQ ID NO: 1), RESIN-F4ICQRCERWCF4Br (RESIN-SEQ ID NO: 2),RESIN-F4ICFHCFSECF4Br (RESIN-SEQ ID NO: 3), RESIN-F4ICAGCFTGCF4Br(RESIN-SEQ ID NO: 4), RESIN-F4ICQLCNVLCF4Br (RESIN-SEQ ID NO: 5),RESIN-YBrCR(T/Q)SC (RESIN-SEQ ID NO: 9) (e.g. RESIN-YBrCRTSC (RESIN-SEQID NO: 10), RESIN-YBrCRQSC (RESIN-SEQ ID NO: 11)) and RESIN-YmICR(T/Q)SC(RESIN-SEQ ID NO: 12) (e.g. RESIN-YmICRTSC (RESIN-SEQ ID NO: 13),RESIN-YmICRQSC (RESIN-SEQ ID NO: 14)). The present sensor and/or arrayof sensors may comprise four of F4ICDICPNHCF4Br-RESIN (SEQ ID NO:1-RESIN), F4ICQRCERWCF4Br-RESIN (SEQ ID NO: 2-RESIN),F4ICFHCFSECF4Br-RESIN (SEQ ID NO: 3-RESIN), F4ICAGCFTGCF4Br-RESIN (SEQID NO: 4-RESIN), F4ICQLCNVLCF4Br-RESIN (SEQ ID NO: 5-RESIN),YBrCR(T/Q)SC-RESIN (SEQ ID NO: 9-RESIN) (e.g. YBrCRTSC-RESIN (SEQ ID NO:10-RESIN), YBrCRQSC-RESIN (SEQ ID NO: 11-RESIN)) and YmICR(T/Q)SC-RESIN(SEQ ID NO: 12-RESIN) (e.g. YmICRTSC-RESIN (SEQ ID NO: 13-RESIN),YmICRQSC-RESIN (SEQ ID NO: 14-RESIN)) or RESIN-F4ICDICPNHCF4Br(RESIN-SEQ ID NO: 1), RESIN-F4ICQRCERWCF4Br (RESIN-SEQ ID NO: 2),RESIN-F4ICFHCFSECF4Br (RESIN-SEQ ID NO: 3), RESIN-F4ICAGCFTGCF4Br(RESIN-SEQ ID NO: 4), RESIN-F4ICQLCNVLCF4Br (RESIN-SEQ ID NO: 5),RESIN-YBrCR(T/Q)SC (RESIN-SEQ ID NO: 9) (e.g. RESIN-YBrCRTSC (RESIN-SEQID NO: 10), RESIN-YBrCRQSC (RESIN-SEQ ID NO: 11)) and RESIN-YmICR(T/Q)SC(RESIN-SEQ ID NO: 12) (e.g. RESIN-YmICRTSC (RESIN-SEQ ID NO: 13),RESIN-YmICRQSC (RESIN-SEQ ID NO: 14)). The present sensor and/or arrayof sensors may comprise five of F4ICDICPNHCF4Br-RESIN (SEQ ID NO:1-RESIN), F4ICQRCERWCF4Br-RESIN (SEQ ID NO: 2-RESIN),F4ICFHCFSECF4Br-RESIN (SEQ ID NO: 3-RESIN), F4ICAGCFTGCF4Br-RESIN (SEQID NO: 4-RESIN), F4ICQLCNVLCF4Br-RESIN (SEQ ID NO: 5-RESIN),YBrCR(T/Q)SC-RESIN (SEQ ID NO: 9-RESIN) (e.g. YBrCRTSC-RESIN (SEQ ID NO:10-RESIN), YBrCRQSC-RESIN (SEQ ID NO: 11-RESIN)) and YmICR(T/Q)SC-RESIN(SEQ ID NO: 12-RESIN) (e.g. YmICRTSC-RESIN (SEQ ID NO: 13-RESIN),YmICRQSC-RESIN (SEQ ID NO: 14-RESIN)) or RESIN-F4ICDICPNHCF4Br(RESIN-SEQ ID NO: 1), RESIN-F4ICQRCERWCF4Br (RESIN-SEQ ID NO: 2),RESIN-F4ICFHCFSECF4Br (RESIN-SEQ ID NO: 3), RESIN-F4ICAGCFTGCF4Br(RESIN-SEQ ID NO: 4), RESIN-F4ICQLCNVLCF4Br (RESIN-SEQ ID NO: 5),RESIN-YBrCR(T/Q)SC (RESIN-SEQ ID NO: 9) (e.g. RESIN-YBrCRTSC (RESIN-SEQID NO: 10), RESIN-YBrCRQSC (RESIN-SEQ ID NO: 11)) and RESIN-YmICR(T/Q)SC(RESIN-SEQ ID NO: 12) (e.g. RESIN-YmICRTSC (RESIN-SEQ ID NO: 13),RESIN-YmICRQSC (RESIN-SEQ ID NO: 14)). The present sensor and/or arrayof sensors may comprise six of F4ICDICPNHCF4Br-RESIN (SEQ ID NO:1-RESIN), F4ICQRCERWCF4Br-RESIN (SEQ ID NO: 2-RESIN),F4ICFHCFSECF4Br-RESIN (SEQ ID NO: 3-RESIN), F4ICAGCFTGCF4Br-RESIN (SEQID NO: 4-RESIN), F4ICQLCNVLCF4Br-RESIN (SEQ ID NO: 5-RESIN),YBrCR(T/Q)SC-RESIN (SEQ ID NO: 9-RESIN) (e.g. YBrCRTSC-RESIN (SEQ ID NO:10-RESIN), YBrCRQSC-RESIN (SEQ ID NO: 11-RESIN)) and YmICR(T/Q)SC-RESIN(SEQ ID NO: 12-RESIN) (e.g. YmICRTSC-RESIN (SEQ ID NO: 13-RESIN),YmICRQSC-RESIN (SEQ ID NO: 14-RESIN)) or RESIN-F4ICDICPNHCF4Br(RESIN-SEQ ID NO: 1), RESIN-F4ICQRCERWCF4Br (RESIN-SEQ ID NO: 2),RESIN-F4ICFHCFSECF4Br (RESIN-SEQ ID NO: 3), RESIN-F4ICAGCFTGCF4Br(RESIN-SEQ ID NO: 4), RESIN-F4ICQLCNVLCF4Br (RESIN-SEQ ID NO: 5),RESIN-YBrCR(T/Q)SC (RESIN-SEQ ID NO: 9) (e.g. RESIN-YBrCRTSC (SEQ ID NO:10-RESIN), RESIN-YBrCRQSC (RESIN-SEQ ID NO: 11)) and RESIN-YmICR(T/Q)SC(RESIN-SEQ ID NO: 12) (e.g. RESIN-YmICRTSC (RESIN-SEQ ID NO: 13),RESIN-YmICRQSC (RESIN-SEQ ID NO: 14)).

In some embodiments the sensor and/or array of sensors comprises astructure F4ICDICPNHCF4Br-RESIN (SEQ ID NO: 1-RESIN), which bindsselenate anion (SeO₄ ²⁻). In some embodiments the sensor and/or array ofsensors comprises a structure F4ICQRCERWCF4Br-RESIN (SEQ ID NO:2-RESIN), which binds selenate anion (SeO₄ ²⁻). In some embodiments thesensor and/or array of sensors comprises a structureF4ICFHCFSECF4Br-RESIN (SEQ ID NO: 3-RESIN), which binds selenate anion(SeO₄ ²⁻).

In some embodiments, the sensor and/or array of sensors comprises astructure F4ICAGCFTGCF4Br-RESIN (SEQ ID NO: 4-RESIN), which bindsselenite anion (SeO₃ ²⁻). In some embodiments, the sensor and/or arrayof sensors comprises a structure F4ICQLCNVLCF4Br-RESIN (SEQ ID NO:5-RESIN), which binds selenite anion (SeO₃ ²⁻). In some embodiments thesensor and/or array of sensors comprises a structure YBrCRTSC-RESIN (SEQID NO: 10-RESIN), which binds selenite anion (SeO₃ ²⁻). In someembodiments, the sensor and/or array of sensors comprises a structureYBrCRQSC-RESIN (SEQ ID NO: 11-RESIN), which binds selenite anion (SeO₃²⁻). In some embodiments, the sensor and/or array of sensors comprises astructure YmICRTSC-RESIN (SEQ ID NO: 13-RESIN), which binds seleniteanion (SeO₃ ²). In some embodiments, the sensor and/or array of sensorscomprises a structure YmICRQSC-RESIN (SEQ ID NO: 14-RESIN), which bindsselenite anion (SeO₃ ²⁻).

In some embodiments, the sensor and/or array of sensors is used formeasuring both selenate and selenite, e.g. to find a ratio of species,and comprises one of F4ICDICPNHCF4Br-RESIN (SEQ ID NO: 1-RESIN),F4ICQRCERWCF4Br-RESIN (SEQ ID NO: 2-RESIN), and 4ICFHCFSECF4Br-RESIN andone of F4ICAGCFTGCF4Br-RESIN (SEQ ID NO: 4-RESIN), F4ICQLCNVLCF4Br-RESIN(SEQ ID NO: 5-RESIN), YBrCRTSC-RESIN (SEQ ID NO: 10-RESIN),YBrCRQSC-RESIN (SEQ ID NO: 11-RESIN), YmICRTSC-RESIN (SEQ ID NO:13-RESIN), and YmICRQSC-RESIN (SEQ ID NO: 14-RESIN)).

In some embodiments, the sensor and/or array of sensors comprises anypeptide described herein.

Methods of Detecting Metals and/or Metalloids

In some aspects, the present invention relates to method for measuring ametal and/or metalloid element. In various embodiments, the methodinvolves contacting a sample comprising a metal and/or metalloid elementwith a sensor or array of sensors that is suitable for concentrating ametal and/or metalloid element and measuring the metal and/or metalloidelement on the sensor or array of sensors.

In some aspects, the invention provides a method for measuring selenium,inclusive of, for example, selenate or selenite, in a sample, forexample a liquid sample. Such method includes, in various embodiments,contacting (e.g., combining) a solution containing selenium and a sensoror array of sensors capable of concentrating the selenium from thesample (e.g. solution). In various embodiments, the method also includesmeasuring a sample of the selenium that is concentrated on the sensor orarray of sensors. The measurement can be, for example, an elementalanalysis method as described herein.

In some aspects, the present invention relates to method for selectivelymeasuring a valence or oxidation state of a metal and/or metalloidelement. In various embodiments, the method involves contacting a samplecomprising a metal and/or metalloid element with a resin that issuitable for concentrating a particular valence or oxidation state ofthe metal and/or metalloid element and measuring a particular valence oroxidation state of metal and/or metalloid element on the resin.

Illustrative metal elements are as follows: 3: Lithium, 4: Beryllium,11: Sodium, 12: Magnesium, 13: Aluminum, 19: Potassium, 20: Calcium, 21:Scandium, 22: Titanium, 23: Vanadium, 24: Chromium, 25: Manganese, 26:Iron, 27: Cobalt, 28: Nickel, 29: Copper, 30: Zinc, 31: Gallium, 37:Rubidium, 38: Strontium, 39: Yttrium, 40: Zirconium, 41: Niobium, 42:Molybdenum, 43: Technetium, 44: Ruthenium, 45: Rhodium, 46: Palladium,47: Silver, 48: Cadmium, 49: Indium, 50: Tin, 55: Cesium, 56: Barium,57: Lanthanum, 58: Cerium, 59: Praseodymium, 60: Neodymium, 61:Promethium, 62: Samarium, 63: Europium, 64: Gadolinium, 65: Terbium, 66:Dysprosium, 67: Holmium, 68: Erbium, 69: Thulium, 70: Ytterbium, 71:Lutetium, 72: Hafnium, 73: Tantalum, 74: Tungsten, 75: Rhenium, 76:Osmium, 77: Iridium, 78: Platinum, 79: Gold, 80: Mercury, 81: Thallium,82: Lead, 83: Bismuth, 87: Francium, 88: Radium, 89: Actinium, 90:Thorium, 91: Protactinium, 92: Uranium, 93: Neptunium, 94: Plutonium,95: Americium, 96: Curium, 97: Berkelium, 98: Californium, 99:Einsteinium, 100: Fermium, 101: Mendelevium, 102: Nobelium, 103:Lawrencium, 104: Rutherfordium, 105: Dubnium, 106: Seaborgium, 107:Bohrium, 108: Hassium, 109: Meitnerium, 110: Darmstadtium, 111:Roentgenium, 112: Copernicium, 113: Ununtrium, 114: Flerovium, 115:Ununpentium, and 116: Livermorium.

Illustrative metalloid elements are as follows: 5: Boron, 14: Silicon,32: Germanium, 33: Arsenic, 34: Selenium, 51: Antimony, and 52:Tellurium.

Selenium, atomic number 34, is a metalloid element. Selenium can befound in −2, 0, +4, and +6 oxidation states. All of these oxidationstates may be detected, i.e. −2, 0, +4, and +6, optionally selectively,using the present invention. For instance, in one embodiment, thepresent invention distinguishes selenate from selenite. For example, thepresent invention may provide a quantitative or qualitative output ofselenate and/or selenite. Alternatively, the present invention may beuseful in determining the ratio selenate to selenite. However, in otherembodiments, the present invention may be useful in determining totalselenium.

Furthermore, in various embodiments, the present invention can detect,optionally selectively, one or more isotopes of selenium, i.e. ⁷⁴Se,⁷⁵Se, ⁷⁶Se, ⁷⁷Se, ⁷⁸Se, ⁸⁰Se, and ⁸²Se.

In various embodiments, the present invention involves or allows for thedetection of a variety of selenium-based compounds, including withoutlimitation: niobium triselenide, oxyselenide, selenium dioxide, seleniumdisulfide, selenium hexafluoride, selenium hexasulfide, seleniummonochloride, selenium oxybromide, selenium oxydichloride, seleniumtetrachloride, selenium tetrafluoride, selenium trioxide, and selenoylfluoride.

Furthermore, in various embodiments, the present invention allows forthe detection of a ratio of a metal and/or metalloid element, inclusiveof selenium, to another element as described elsewhere herein.

The present invention finds use, in some embodiments, in environmentaldetection and protection. For instance, the present invention may beused to assess metal and/or metalloid contamination (e.g. seleniumcontamination) in soil and/or groundwater (e.g. at current or abandonedindustrial sites). In some embodiments, the invention relates toenvironmental cleanup and remediation, e.g. the treatment of brownfieldland. The present invention finds use, in some embodiments, in detectionof metal and/or metalloid concentrations (e.g. selenium concentration)in wastewater. The present invention finds use, in some embodiments, indetection of metal and/or metalloid concentrations (e.g. seleniumconcentration) in wastewater near power plants and industrial sources.

The present invention finds use in monitoring human consumption of metaland/or metalloid elements (e.g. selenium). For instance, the presentinvention, in various embodiments, relates to analysis of drinkingwater. For instance, the present invention, in various embodiments,relates to analysis of the portability of water. In other embodiments,the present invention allows for measuring metal and/or metalloidelements (e.g. selenium) in food or soil (e.g. of agricultural spaces).

Further, and relatedly, the present invention, in various embodiments,relates to analysis, e.g. quality monitoring, of one or more ofenvironmental water, ground water, surface water, and wastewater.

In various embodiments, the present invention relates to detection ofelements before and after environment treatments. For example, in someembodiments, the present invention provides a means to compare asample's metal and/or metalloid (e.g. selenium) elemental compositionbefore and after treatments. For example, such methods can evaluate thesuccess or failure of methods for removing metal and/or metalloid (e.g.selenium) element from a sample, including ion exchange. In the case ofselenium, the present methods may be used to evaluate the success orfailure of one or more of activated alumina, coagulation/filtration,lime softening, reverse osmosis, and electrodialysis to remove seleniumfrom a sample.

Selenium has been characterized as an environmental source of pollution,e.g. from waste materials from certain mining, agricultural,petrochemical, and industrial manufacturing operations. For example, inBelews Lake, N.C., 19 species of fish were eliminated from the lake dueto 150-200 μg Se/L wastewater discharged from 1974 to 1986 from a DukeEnergy coal-fired power plant. Also, at the Kesterson National WildlifeRefuge in California, thousands of fish and waterbirds were poisoned byselenium in agricultural irrigation drainage.

U.S. EPA has set a maximum contaminant level goals (MCLG) for seleniumof 0.05 mg/L or 50 ppb. In various embodiments, the present inventionmay be used to confirm compliance with such standard.

Illustrative Analytes

The methods, compositions and apparatus described herein can becompatible with complex fluid matrix carriers of an analyte such ametal- and/or metalloid-containing analyte (e.g., wherein the analyte isdissolved, suspended or otherwise combined with). For instance, theanalyte can contain selenium. For example solutions utilized can be fromagricultural run-off. Fertilizers can contain trace amounts of seleniumand such run-off can include selenate and selenite ions. Other exampleinclude run-off, e.g. wastewater, from mining operations and powerplants. For example, when coal-bearing strata are exposed to air andwater during the mining process, and when coal is washed prior totransportation and distribution. Such runoff as from agriculture, coaland petroleum operations can include many other ions and othermaterials.

In other examples, the solution utilized can include a biological fluid(e.g., including biological stimulant). The biological fluids can be, orbe formulated to simulate, the fluids extracted or produced from plants,animals, humans, yeast and/or bacteria. Such fluids can be naturallysourced or are simulated (e.g., including using naturally sourceingredients and/or unnaturally sourced ingredients). For example, suchfluids can include blood plasma, synovial fluid, urine, gastric fluid(e.g., fasted-state gastric fluid or fed-state gastric fluid),intestinal fluid, (e.g., fasted-state intestinal fluid, fed-stateintestinal fluid) colonic fluid, fasted-state colonic fluid, fed-statecolonic fluid, saliva, lung fluid, fluid from exhaled breath, vaginalfluid, semen, tears, sweat, cerebrospinal fluids, cerumen, endolymph,perilymph, feces, milk, bronchial fluids, amniotic fluid, aqueous humor,vitreous humor, bile, chyle, chyme, exudate, intracellular fluid,interstitial fluid, lymphatic fluid, transcellular fluid, plantexudates, female ejaculate, gastric acid, gastric juice, mucus,pericardial fluid, pleural fluid, pus, rheum, sebum, sputum, vomit, andmixtures of these. Such fluids can be derived from an animal, e.g.human, believed to have been exposed a metal and/or metalloid element,such as selenium. Such fluids can include many compounds and can beundefined or uncharacterized.

Detection Methods/Measurements/Elemental Analysis

In various embodiments, the present methods, apparatus, sensors and/orarray of sensors, and compositions use, or can be used with, a varietyof detection methods, including, without limitation x-ray fluorescence,atomic absorption spectroscopy, atomic emission spectroscopy, massspectrometry, and laser induced breakdown spectroscopy.

X-ray fluorescence spectroscopy can be a useful method for theimplementation of some of the embodiments herein described. X-rayfluorescence spectrometry is a spectroscopic technique that can be usedto determine one or more chemical elements (e.g., heavy metals) that arepresent in a sample, such as can be present in an analyte, a molecule, apolymer, a mineral, an organelle, a tissue, a biological fluid, anorgan, an inorganic materials (e.g., clays, sands, silt, rocks and loworganic containing soils), organic material (e.g., biomass such asplants, animals, insects, yeast, bacterial and/or high organiccontaining soil) or other substrates. The method can be used toqualitatively identify and also quantify the elements present and relieson the underlying physical principle that when an atom of a particularelement is irradiated with x-ray radiation, the atom ejects a coreelectron such as a K, L or M shell electron. The resulting atom is in anexcited state, such as a 1S¹ excited state, and it can return to theground state by replacing the ejected electron with an electron from ahigher energy orbital. This transition is accompanied by the emission ofa photon, in the process known as x-ray fluorescence, and the photonenergy is equal to the difference in the energies of the two orbitals.Each element has a characteristic set of orbital energies and therefore,a characteristic x-ray fluorescence spectrum. For example, each elementwill have a characteristic x-ray energy signal corresponding to theenergies of the K, L and M electron shells of each element.

X-ray fluorescence can be generated by excitation of atoms by a beam ofelectrons, particles and/or x-rays. Samples, such as described herein,subjected to such excitation can produce x-ray fluorescence due to theelements in the samples and one or more of the elements can bemonitored. For example, Particle-Induced X-ray Emission (PIXE) and X-rayFluorescence (XRF) can be used. In some embodiments, XRF is used in theembodiments described herein. In some embodiments, μ-XRF is used.

In some embodiments, the x-ray fluorescence is energy dispersive x-rayfluorescence. Optionally, the x-ray fluorescence utilizes polychromaticx-rays for exciting the sample. In some embodiments the analysis methodis an x-ray fluorescence that utilizes a micro-focus x-ray tube.Optionally, the x-ray fluorescence utilizes a focusing optic.

An x-ray fluorescence spectrometer is an apparatus capable ofirradiating a sample with an x-ray beam, and detecting the x-rayfluorescence from the sample. The irradiation can be produced by varioussources, such as synchrotron radiation, a radioactive source or an x-raytube. Synchrotron radiation can produce a monochromatic x-ray beam witha very high intensity. The bending, beam focusing and particleacceleration needed to produce synchrotron radiation requires a largerscale facility with concomitant expenses. Regarding radioactive sources,x-rays from radioactive primary sources such as ⁵⁵Fe, ¹⁰⁹Cd and ²⁴¹Amcan be made to strike a secondary exciter target, e.g., tin, and thecharacteristic x-rays from the exciter target are aimed at the unknownsample. Radioactive sources produce beams with the characteristic linesof the secondary exciter target and have very low energies elsewhere.X-ray tubes produce polychromatic x-rays including a very broad“Bremsstrahlung” radiation band and characteristic emission peaks. X-raytubes offer analytical flexibility in the beam energies, for example bychanging the applied voltage and target material of the x-ray tube.Filters can also be added to narrow or exclude certain energies (e.g.,high pass, low pass or band pass filters). Focusing optics can be usedsuch as collimators and/or concentrators (e.g., mono capillary andpolycapillary) to produce spot sizes smaller than a millimeter indiameter. The fluorescence can be detected in at least two ways, usingwavelength dispersive or energy dispersive methods. Wavelengthdispersive detectors work by reflecting sample radiation onto ananalyzing crystal and measurement of the angle of reflection followed bycalculation of the wavelength using Bragg's Law. Energy dispersivedetectors work by generating a signal that is proportional to theabsorbed energy of a single photon. For example, solid state detectorsinclude gas filled detectors and semiconductor detectors (e.g., PINdiode, silicon drift detectors, Si(Li), SI PIN detector, silicon driftdetector, SiLi detector, CdTe, Diamond, Germanium detectors, ion chamberdetectors, and the like). The angle of excitation and detector can bebetween about 0 and about 180 deg. For example angles can be betweenabout 5 DEG and about 95 DEG such as for XRF and μ-XRF. In someinstances very low angles, such as below 0.5 DEG can be used, such aswhen using Total Reflection X-ray Fluorescence (TXRF) and grazingemission x-ray fluorescence. The above methods and components can beutilized to detect x-ray fluorescence in the samples described herein,including using modified commercial equipment. In some embodiments, themethods use at least one x-ray tube (e.g., having Cu, Mo, Cr, W or Rhtargets), polycapillary focusing optics and one or more solid statedetectors (e.g., one or two detectors). For example, polychromaticx-rays generated from an x-ray tube can be focused to less than 5 mmdiameter (e.g., less that about 4 mm diameter, less than about 3 mmdiameter, less than about 2 mm diameter, less than about 1 mm diameter,less than about 750 μm diameter, less than about 500 μm diameter, lessthan about 100 μm diameter or even less than about 50 μm diameter) spotsize and detected using a silicon drift detector.

In various embodiments, the present invention provides for alterationsof the x-ray fluorescence spectrometer to allow for efficient detectionof desired analytes. For instance, the x-ray fluorescence spectrometermay be altered to provide excitation at photon energies that are bestsuited for the desired analytes. For example, the choice of x-ray tubematerial, excitation filters or monochrometer may be altered to bestsuit the desired analytes.

X-ray fluorescence is inefficient relative to the excitation energy ofthe exciting beam (e.g., x-ray excitation beam). For light elements, forexample with atomic numbers below about 10, the fluorescence yields arepractically zero for all lines. Above about atomic number 10 theefficiency for the K line increases from zero to only about 0.1 atatomic number 20 after which it starts rising more significantly. Theefficiency for the L line is zero until about atomic number 30 and isonly about 0.1 for atomic number 60. In some instances, it isadvantageous to maintain a vacuum between the sample and detector pathto mitigate the attenuation due to components in air especially forlighter elements (e.g., between atomic number 10 and about 20).Optionally, the path between the sample and detector can be kept underan atmosphere of a light element such as helium.

In energy dispersive XRF, the characteristic radiation of a particularline can be described approximately as a Gaussian function (e.g., adetector response function). The spectral background results from avariety of processes such as incoherent scattered primary radiation andtherefore depends on the shape of the excitation spectrum and on thesample composition. In embodiments, the characteristic signal of ananalyte (e.g., element) of interest such as a heavy metal produces asignal in at least one area of the spectrum such as a peak with a signalto noise ratio of at least 3. One method to obtain the net data areaunder a line of interest consists of interpolating the background underthe peak and summing the background-corrected channel contents in awindow over the peak. This approach can be limited by the curvature ofthe background and by the presence of other peaks and other peakdeconvolution methods can be used to better resolve the spectrum. Aresolved peak is understood that the peak energy (e.g., position) andcounts under a peak (e.g., integrated area) can be determined andassociated to a particular element.

A widely used method for peak resolution (e.g., deconvolution) isnon-linear least squares fitting of the spectral data with an analyticalfunction. This algebraic function, including all important parameters(e.g., net areas of the fluorescent lines, their energy and resolution)is used as a model for the measured spectrum. It consists of thecontribution from all peaks (e.g., modified Gaussian peaks withcorrections for low-energy tailing and escape peaks) within a certainregion of interest and the background (e.g., described by, for example,linear or exponential polynomials). The optimum values of the parametersare those for which the difference between the model and the measuredspectrum is minimal. Some of the parameters are nonlinear, and aminimization procedure is selected such as the Marquardt algorithm.

Another method for peak resolution applies a top-hat filter to suppresslow frequency components in the spectrum. This method reduces or eveneliminates the background but also can distort the spectrum. In themethod, the top hat filter is applied to a well-defined referencespectrum (e.g., of know concentrations of elements) as well as theexperimental spectrum with unknowns and the two are compared. Thecomparison can be, for example, by applying a multiple linearleast-squares fitting to the filtered spectra resulting in the net peakareas of interest.

Other deconvolution protocols can be used to resolve the peaks ofinterest. Backgrounds can vary between about zero counts per second(cps) and about 10,000 cps dependent at least in part on thedeconvolution protocol used. It is be understood by those skilled in theart what protocol can be utilized.

Further methods involving x-ray fluorescence are described in U.S. Pat.Nos. 7,858,385; 7,519,145; 7,929,662, and 9,063,066 and U.S. PatentPublication No. 2008-0220441, the entire contents of which areincorporated herein.

In addition to x-ray fluorescence, other elemental analysis methods andtheir corresponding instruments that are capable of measuring a metaland/or metalloid may also be used with the present invention. Thesemethods include atomic absorption spectroscopy, where the elementalanalysis is performed by atomizing the sample and measuring thetransmittance of light of various wavelengths through the atomizedsample; atomic emission spectroscopy, where the sample is excited, oftenby burning, and the wavelength and intensity of the emitted light ismeasured and correlated to the elemental composition of the sample; massspectrometry; and laser induced breakdown spectroscopy, which is aparticular type of atomic emission spectroscopy where the excitation isprovided by a laser.

Quantitative Detection

In some embodiments the methods, apparatus and compositions describedherein can be utilized to analyze an element, e.g. a metal and/ormetalloid element, e.g. selenium present in a sample at variousconcentrations across a wide dynamic range. In various embodiments, thediffering affinities of the various sensors and/or arrays of sensorsallow for this detection over a measurable dynamic range. In variousembodiments, the measurement can be made in real time, e.g. at the pointof sampling.

In various embodiments, the measurement is made on sensors that arestill in contact with the sample to be analyzed. In various embodiments,the measurement is made on sensors that are not in contact with thesample to be analyzed, e.g. have been removed from the sample.

In some embodiments the methods, apparatus and compositions describedherein can be utilized to analyze an element, e.g. a metal and/ormetalloid element, e.g. selenium present in a sample at concentrationsabove about 50 parts per billion, or above 500 parts per billion, orabove one part per million.

For instance, in some embodiments the methods, apparatus andcompositions described herein can be utilized to analyze an element,e.g. a metal and/or metalloid element, e.g. selenium, present in asample at concentrations above about 50 ppb, or above about 75 ppb, orabove about 100 ppb, or above about 150 ppb, or above about 200 ppb, orabove about 250 ppb, or above about 300 ppb, or above about 350 ppb, orabove about 400 ppb, or above about 450 ppb, or above about 500 ppb, orabove about 550 ppb, or above about 600 ppb, or above about 650 ppb, orabove about 700 ppb, or above about 750 ppb, or above about 800 ppb, orabove about 850 ppb, or above about 900 ppb, or above about 950 ppb, orabove 1 ppm, or above 5 ppm, or above 10 ppm, or above 100 ppm. In someembodiments the methods, apparatus and compositions described herein canbe utilized to analyze an element, e.g. a metal and/or metalloidelement, e.g. selenium, present in a sample at concentrations at orbelow about 10 ppb, or at or below about 25 ppb, or at or below about 50ppb, or at or below about 75 ppb, or at or below about 100 ppb, or at orbelow about 150 ppb.

Apparatus

In various embodiments, the present invention provides an apparatuswhich finds use in, for instance, measuring metals and/or metalloids,such as selenium, that have been absorbed on a solid support, e.g.resin. In various embodiments, the present invention provides anapparatus comprising the resins described herein.

By way of illustration, FIG. 1 shows an embodiment of an apparatus formeasuring various metal and/or metalloid elements, such as selenium thathas been absorbed on solid support, e.g. resin. The apparatus 100includes an x-ray excitation source 110 an x-ray detector 112, and asensor and/or array of sensors 114 (e.g., without limitation as shown inFIG. 2), which is described in more specific detail elsewhere herein.The sensor and/or array of sensors can contain a solid support, e.g.resin, which can be in the form of a bead which chelator molecules 116attached thereupon. The chelator molecules can bind a species such as ametal- and/or metalloid-containing species 118. The excitation source isconfigured to irradiate the solid support with x-rays 120. The detectoris configured to detect fluorescing x-rays 122 emitted from the solidsupport, e.g. resin.

FIG. 1 depicts a single x-ray source and single detector. Use ofmultiple detectors can increase the detection limit. For example, usingtwo detectors can double the sensitivity, lowering the detection limitby about thirty percent or doubling the measurement speed (e.g., from 60seconds per measurement to 30 seconds per measurement). Alternatively, asemiconductor with a larger active surface can also have the sameeffect.

This invention is further illustrated by the following non-limitingexample.

EXAMPLES Example 1: Detection of Selenium

X-ray fluorescence measurements were obtained with an x-ray fluorescencespectrometer equipped with a microfocus rhodium x-ray tube equipped witha polycapillary focusing optic as the x-ray excitation source, and anenergy dispersive silicon drift detector as the x-ray detector, andresins disposed to be excited by the x-ray tube and disposed such thatemission from the resin and any selenium bound to the resin weremeasured by the x-ray detector, as shown in FIG. 1. Measurements wereobtained for selenium and bromine.

The following were resins studied (as noted in FIG. 4 and FIG. 5, on theX-axes):

Sequence 1. F4ICDICPNHCF4Br-PEG4-Polystyrene (SEQ ID NO:1-PEG4-Polystyrene),

Sequence 2. F4ICQRCERWCF4Br-PEG4-Polystyrene (SEQ ID NO:2-PEG4-Polystyrene),

Sequence 3. F4ICFHCFSECF4Br-PEG4-Polystyrene (SEQ ID NO:3-PEG4-Polystyrene),

Sequence 4. F4ICAGCFTGCF4Br-PEG4-Polystyrene (SEQ ID NO:4-PEG4-Polystyrene),

Sequence 5. F4ICQLCNVLCF4Br-PEG4-Polystyrene (SEQ ID NO:5-PEG4-Polystyrene), and

Sequence 6. YBrCR(T/Q)SC-Polystyrene (SEQ ID NO: 9-Polystyrene).

The following solutions were prepared. A “Selenite Solution” wasprepared of water having a concentration of selenite of 50 parts perbillion. A “Selenate Solution” was prepared of water having aconcentration of selenate of 50 parts per billion. A “Wash Solution” wasprepared of water having a concentration of sodium chloride of 2 molar.

As shown in FIG. 4, resins 1-3 were measured by x-ray fluorescence toestablish a baseline selenium signal, which was standardized to thebromine signal from the resin. Resins 1-3 were then exposed to theSelenate Solution for 12 hours, then measured by x-ray fluorescence, atwhich time the resins showed elevated selenium signals relative to theirbaseline selenium signal. Resins 1-3 were then exposed to the WashSolution for 12 hours, then measured by x-ray fluorescence, at whichtime they showed selenium signals equal to or less than their baselinesignals. Resins 1-3 were then exposed to the Selenate Solution for 12hours, then measured by x-ray fluorescence, at which time the resinsshowed elevated selenium signals relative to their baseline seleniumsignal. Resins 1-3 were then exposed to the Wash Solution for 12 hours,then measured by x-ray fluorescence, at which time they showed seleniumsignals equal to or less than their baseline signals. Resins 1-3 werethen exposed to the Selenite Solution for 12 hours, then measured byx-ray fluorescence, at which time the resins showed selenium signalsequal to or less than their baseline signals. Resins 1-3 were thenexposed to the Wash Solution for 12 hours, then measured by x-rayfluorescence, at which time they showed selenium signals approximatelyequal to or less than their baseline signals.

As shown in FIG. 5, Resins 4-6 were measured by x-ray fluorescence toestablish a baseline selenium signal, which was standardized to thebromine signal from the resin. Resins 4-6 were then exposed to theSelenite Solution for 12 hours, then measured by x-ray fluorescence, atwhich time they showed elevated selenium signals relative to theirbaseline selenium signal. Resins 4-6 were then exposed to the WashSolution for 12 hours, then measured by x-ray fluorescence, at whichtime they showed selenium signals equal to or less than their baselinesignals. Resins 4-6 were then exposed to the Selenite Solution for 12hours, then measured by x-ray fluorescence then measured by x-rayfluorescence, at which time they showed elevated selenium signalsrelative to their baseline selenium signal. Resins 4-6 were then exposedto the Wash Solution for 12 hours, then measured by x-ray fluorescence,at which time they showed selenium signals equal to or less than theirbaseline signals. Resins 4-6 were then exposed to the Selenate Solutionfor 12 hours, then measured by x-ray fluorescence, then measured byx-ray fluorescence, at which time the resins showed elevated seleniumsignals relative to their baseline selenium signal. Resins 4-6 were thenexposed to the Wash Solution for 12 hours, then measured by x-rayfluorescence, at which time they showed selenium signals approximatelyequal to or less than their baseline signals.

Other than in the examples herein, or unless otherwise expresslyspecified, all of the numerical ranges, amounts, values and percentages,such as those for amounts of materials, elemental contents, times andtemperatures of reaction, ratios of amounts, and others, in thefollowing portion of the specification and attached claims may be readas if prefaced by the word “about” even though the term “about” may notexpressly appear with the value, amount, or range. Accordingly, unlessindicated to the contrary, the numerical parameters set forth in thefollowing specification and attached claims are approximations that mayvary depending upon the desired properties sought to be obtained by thepresent invention. At the very least, and not as an attempt to limit theapplication of the doctrine of equivalents to the scope of the claims,each numerical parameter should at least be construed in light of thenumber of reported significant digits and by applying ordinary roundingtechniques.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the invention are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspossible. Any numerical value, however, inherently contains errornecessarily resulting from the standard deviation found in itsunderlying respective testing measurements. Furthermore, when numericalranges are set forth herein, these ranges are inclusive of the recitedrange end points (e.g., end points may be used). When percentages byweight are used herein, the numerical values reported are relative tothe total weight.

Also, it should be understood that any numerical range recited herein isintended to include all sub-ranges subsumed therein. For example, arange of “1 to 10” is intended to include all sub-ranges between (andincluding) the recited minimum value of 1 and the recited maximum valueof 10, that is, having a minimum value equal to or greater than 1 and amaximum value of equal to or less than 10. The terms “one,” “a,” or “an”as used herein are intended to include “at least one” or “one or more,”unless otherwise indicated.

Any patent, publication, or other disclosure material, in whole or inpart, that is said to be incorporated by reference herein isincorporated herein only to the extent that the incorporated materialdoes not conflict with existing definitions, statements, or otherdisclosure material set forth in this disclosure. As such, and to theextent necessary, the disclosure as explicitly set forth hereinsupersedes any conflicting material incorporated herein by reference.Any material, or portion thereof, that is said to be incorporated byreference herein, but which conflicts with existing definitions,statements, or other disclosure material set forth herein will only beincorporated to the extent that no conflict arises between thatincorporated material and the existing disclosure material.

While this invention has been particularly shown and described withreferences to preferred embodiments thereof, it will be understood bythose skilled in the art that various changes in form and details may bemade therein without departing from the scope of the inventionencompassed by the appended claims.

As used herein, all headings are simply for organization and are notintended to limit the disclosure in any manner. The content of anyindividual section may be equally applicable to all sections.

What is claimed is:
 1. A sensor or array of sensors comprising achelator molecule, wherein the chelator molecule comprises a peptide,the peptide having a general formula of:F₁CZ₁Z₂CZ₃Z₄Z₅CF₂, wherein: F₁ and F₂ are each independently aphenylalanine derivative of the structure:

wherein X is a halogen; C is a cysteine amino acid; and Z₁, Z₂, Z₃, Z₄,and Z₅ are each independently an amino acid.
 2. The sensor or array ofsensors of claim 1, wherein F₁ is 4-iodophenylalanine (F4I).
 3. Thesensor or array of sensors of claim 1, wherein F₂ is4-bromophenylalanine (F4Br).
 4. The sensor or array of sensors of claim1, wherein the peptide comprises one or more amino acid sequences ofF4ICDICPNHCF4Br (SEQ ID NO: 1), F4ICQRCERWCF4Br (SEQ ID NO: 2),F4ICFHCFSECF4Br (SEQ ID NO: 3), F4ICAGCFTGCF4Br (SEQ ID NO: 4), andF4ICQLCNVLCF4Br (SEQ ID NO: 5), wherein F4I is 4-iodophenylalanine andF4Br is 4-bromophenylalanine.
 5. The sensor or array of sensors of claim1, wherein Z₁, Z₂, Z₃, Z₄, and Z₅ are each independently an amino acidselected from D, I, P, N, H, Q, R, E, W, S, A, G, F, T, L, V, ormodifications thereof.